It is something that is regularly trotted out in the media – the ordering of unnecessary testing by doctors caused by the fear of litigation. The recent decision of the NSW Supreme Court in Rothonis v Lattimore brings a healthy dose of common sense and pragmatism to the table.

The plaintiff was a young mother of [4] who, in August 2006 experienced altered vision and consciousness whilst driving. The plaintiff’s husband was a general practitioner and he arranged for a CT scan of the plaintiff’s head and neck which suggested the plaintiff had suffered a lacunar infarct, an area of dead brain tissue which would indicate that there had been a loss of blood supply to that area of the brain for a period of time, most likely due to a blockage in an artery.

Naturally anxious to rule out any sinister any underlying cause which could potentially lead to further such events, the plaintiff’s husband referred her to the defendant, who was a cardiologist, and a neurologist.

Various testing performed by the defendant all came back as normal, with the exception of a transthoracic echocardiogram. That testing revealed that the plaintiff had a highly mobile atrial septum – the wall between the right and left atrium. When blood returns from the body into the heart in enters the right atrium. The heart contracts forcing the blood into the right ventricle and from there it passes into the lungs before returning to the heart via the left atrium, into the left ventricle and out into the arterial blood stream. With a mobile atrial septum, when the right atrium compresses, as well as blood being forced down into the right ventricle, the atrial septum (the thin wall between the left and right atrium) bulges laterally or sideways, into the left atrium. In some cases there is also a hole in the septum which allows blood returning from the body to pass directly into the left atrium and the arterial blood stream, without first passing through the lungs – this is called a patent foramen ovale (PFO).

The plaintiff’s MRI confirmed that she had not in fact suffered any ischaemic event in the brain. On this basis, and consistent with the plaintiff’s symptom descriptions and history, the neurologist diagnosed her as having suffered a migrainous episode.

The defendant gave evidence that when an ischaemic event has occurred, a cardiologist’s role is to investigate and eliminate a potential cardiac cause. Once the MRI had ruled out an ischaemic event and the neurologist had confirmed the diagnosis of a migrainous episode, in the defendant’s view, no further investigation was required.

In mid 2007 the plaintiff suffered a serious stroke that left her with considerable disabilities and deficits. The plaintiff was also found to have a PFO that was surgically repaired.

The plaintiff alleged that on finding the mobile septum, the defendant should have organized a further test (a transoesophageal echocardiogram) to ascertain whether a PFO was present, and upon confirming that it was, to have either prescribed anti-coagulant or anti-platelet medication, and/or performed surgical closure of the PFO. She alleged that this would have prevented the stroke that she ultimately suffered.

The defendant argued that given her young age, the absence of any history of an ischaemic event, it was not necessary to conduct any additional investigations. Further, the additional investigation was not warranted because it was invasive and carried a risk to the plaintiff, and that even if a PFO had been identified, no additional treatment would have been ordered.

There was expert evidence at the trial that in 2006, and even at the date of the trial, there was no clear medical link between a patient having a PFO and an increased risk of stroke. The experts agreed that in the absence of any other identified cause for the stroke, it likely occurred when a clot in the blood returning from the body passed directly into the left atrium and back into the blood stream, rather than being filtered out in the lungs. However, some 1 to 2% of the population has a PFO combined with an aneurysm (as the plaintiff did) and only a very small proportion of those ever go on to have a stroke. This would mean that additional testing would be required on 1 in 100 or 1 in 50 patients, and the scientific evidence with respect to causation simply does not justify that rate of testing.

The court found for the defendant on both liability and causation. In considering the defence of peer professional opinion [1], the court noted that this section operates as a defence to what otherwise would be considered to be a departure from the expected duty of care. Here, there having been no breach, the defence had no application.[2]

This case should assist to assure practitioners that it is not necessary to order every available test in order to exclude every potential diagnosis. It also reinforces that the law does not require perfection, rather reasonable care remains the appropriate determinant of a practitioner’s conduct.